What is the Difference Between Doppler Effect in Sound and Light?

The Doppler effect is the change in the frequency of a wave relative to an observer due to the relative motion between the observer and the source. The key difference between the Doppler effect in sound and light lies in their velocities, medium dependencies, and the theory of relativity. Here are the main differences:

1. Velocity: The Doppler effect in sound depends on the relative velocity of the observer and the source, which is relative to the medium (usually air) through which the sound waves pass. In contrast, the Doppler effect in light only considers the relative difference in velocity between the observer and the source, as the speed of light is always fixed according to the theory of relativity.
2. Medium Dependency: Sound waves require a medium to propagate, while light waves do not. The Doppler effect for sound is influenced by the medium, whereas the Doppler effect for light is not.
3. Relativity: The theory of relativity states that the speed of light is constant for all observers, regardless of their relative motion. This means that the Doppler effect for light is fundamentally different from that for sound, as the velocity of the observer or source does not affect the speed of light.

In summary, the Doppler effect in sound involves changes in speed, frequency, and wavelength due to relative motion and medium dependencies, while the Doppler effect in light only considers the relative difference in velocity between the observer and the source, with no medium dependency and a fixed speed of light.

Comparative Table: Doppler Effect in Sound vs Light

The Doppler effect is a phenomenon observed in both sound and light, where the observed frequency and wavelength of a wave change if the source of the wave and the observer are in relative motion. Here is a table comparing the Doppler effect in sound and light:

The key difference between the Doppler effect in sound and light is that, for sound, the velocity of the observer and the source are relative to the medium in which the waves go through, whereas for light, only the relative difference in velocity between the observer and the source is important. Additionally, sound requires a medium to propagate, while light does not.